Pneumatic chuck for automatic turret lathes



July 24, 1951 J. nousA 2,561,789

PNEUMATIC CHUCK FOR AUTOMATIC TURRET LATHES Filed Jan. 15, 1949 INVENTORing cylinder can be effected only with consider- 2,561,789` ,1 PNEUMATICoHUCkroRaUroM TURRET .laroslav Upousmyllobrany, (Czechoslovakia, `as.-`i signortcjskodaworks,Nationaliorporation, ,p

Plzen; Czechoslovakia Ann Q2 claims.

Thisfinvention relates to. chucks Landtgllrlore ,particularly, to animproved pneumatiemorair operated chuck` for lathes/.m

The increased" outputsfrequired of lathes resultirigflfrom the useori-hardtmetal toolstneces'si-'lfi a i -ta`tes` the .use of.amoreeincientclampinglzdevice posed to pressure throughout `theduration of clamping rotates with the spindle increasing thussubstantially, due to its large diameter necessary for exerting asuincient clamping force, the inertia forces of the` spindle box, suchsubstantial increase of `the'inertia forcesresulting in a veryundesirable overloading of the motor on starting and braking of thelatter.

(er. 2te, "4)

Moreover, the air feed into the rotating workable difculties, as packingof the respective elements is difficult, thus causing air losses.Additionally jamming of the air feed socket at high speeds is oftenliable to occur.

All the above mentioned drawbacks 'are eliminated in the pneumaticholding device or air operated chuck according to the presentinventions, and which is characterized by the following outstandingnovel features: The operating force is exerted by a fixed cylinder whichhas air pressure applied to its axially movable operating piston onlyduring the actual clamping and releasing operations. Theactual holdingor gripping is maintained by chucking fingers, operated by the piston,and being self-locking when so operated. In addition, the operatingmechanism is characterized by ease of operation and control.

With the foregoing in mind, it is an object of the present invention toprovide an improved air operated chuck for lathes or the like.

Another object is to provide such a chuck including a non-rotatableoperating cylinder having an axially movable piston, and self-lockingchuck operating fingers whereby the cylinder need be energized onlyduring the clamping and release movements and need not be energizedduring the chuck holdingtime.

These, and other objects, advantages and novel features of the inventionwill be apparent from l Y@In the drawing the: `followingdescription andvthe accompanying r fpfFigs. .l'and ,i2 are schematic`views.illustrating Athe-.principlesoffitheiinvention. i

l .Figiuis antelevationfview, partly inrsection, nf

a practical embodiment of the invention.

In Fig. l, the mechanism is shown in a position where the chuckingdevice is released by introe i ducing pressure air in a direction a. Thepiston i', moving inside the xed cylinder I, is then in its extremeleft-hand position. A sleeve 3 is rotatably mounted within piston 2 onball bearings 1,

andis secured to rotate with the spindle 5 and chuck operating thrusttube 6. Within sleeve 3 are mounted bell crank chucking fingers 4, whichare pivotally supported by a member secured to spindle 5. The outer endsofthe longer arms of bell cranks 4 are engaged in peripheral openings inthe medial portion of sleeve 3, whereas the ends of the shorter arms ofthe bell cranks bear against jaws or claws 8 secured to thrust tube 6.Thrust tube 6 is axially movable relative to `spindle 5. Consequently,rocking of cranks 4, which are pivoted on spindle 5, will move jaws 8attached to tube 6. Thus, tube 6 will be moved axially to operate thechuck 9 (Fig. 3). In Fig. 1, with piston 2 at its extreme left-hand orouter position, the bell cranks 4 have been swung by sleeve 3 to aposition substantially releasing claws 8, so that tube S can move to theright to release chuck 9.

By introducing pressure air ina direc-tion b (see Fig. 2), the piston 2is moved into its extreme righthand position carrying with it the sleeve3. The chucking nngers, by means of the engagement of sleeve 3 withtheir longer arm, are rocked to a position in which the axes of theirshorter arms are parallel to the'axis of the spindie 5 whereby aself-locking arrangement of the holding cranks 4 is attained, theshorter arms-of the chueking fingers being stressed in an axialdirection. In the `position of Fig. 2, jaws 8 and tube 6 are moved tothe right to engage the chuck.

The movement of the chucking fingers 4 held in the attachment of saidthrust tube 6 is transmitted by the latter to the cone encircling thechuck S which latter thus holds rmly the material to be machined, as isclear from Fig. 3 illustrating a practical embodiment of the invention.

The chucking range is sutlicient even for rolled material and the wholedevice functions dependably even at high angular velocities, such as6000 R. P. M. or greater.

While a specific embodiment of the invention has been shown anddescribed in detail to illus- 1. In a machine'having arotating spindle,a

chuck operatively associated with the spindle, and a chuck operatingelement movable axially relative tothe spindle, chuck operatingmechanism second arms are parallel to the spindle axis and force saidabutment means and element to va chuck operated position, and a secondposition in which said bell cranks are rocked by said sleeve to aposition substantially releasing said abutment means. I

comprising in combination, a stationary fluid x pressure cylinder; apiston non-rotatably mounted in said cylinder and coaxially embracingsaid spindle; means for selectively admitting pressure fluid to saidcylinder to move said piston axially relative to the spindle; radiallyswingablebell y cranks pivotally mounted on said spindle'within saidpiston and each having a irst arm and a second arm extending from thepivot axis; a sleeve rotatably mounted v/ithin said piston and xed:against vaxial movement relative thereto,

said sleeve being engaged with said rst arms; and abutment means fixedto said operating ele- ?inent, said Asecond arms being engageable withY,Y

.25 :Numberl said abutment means; said piston and sleevebeing movablebetween a rst position in which said 2. Chuck operating mechanism asclaimed in claim 1 in which said operating element comprises a tubularelement coaxial with the spindle.

JARosLAv DoUsA.

REFERENCES Crm1) i The following` references are of record in the le ofthis patent:

UNITED STATES PATENTS l Name Dater -Cutler Nov. 23, 1926V 'romains Aug.2, 1932 Redmer* v Jan. 15, 1946 Eaton l l Dec. f7, 1948 -Rauch n s fFeb.r22, 1.949

FOREIGN PATENTS Country i Date 1 Great Britain Dec. 5.,i1934 Number

